1. Field of the Invention
The invention relates to a semiconductor device and a method of manufacturing the same, particularly, a CSP (Chip Size Package) type semiconductor device and a method of manufacturing the same.
2. Description of the Related Art
A CSP has received attention in recent years as a new packaging technology. The CSP is a small package having about the same outside dimensions as those of a semiconductor die packaged in it. A BGA (Ball Grid Array) type semiconductor device has been known as a type of the CSP. The BGA type semiconductor device has a plurality of ball-shaped conductive terminals made of metal such as solder arrayed on one side of the package.
A thinner semiconductor die has been required for increasing packaging density. For satisfying this, it is necessary to thin a semiconductor substrate. However, a thinner substrate may not be carried in a manufacturing process since it warps or breaks due to its low strength. Therefore, a supporting body such as a glass substrate or a protection tape is attached to one surface of a semiconductor substrate, and the other surface where the supporting body is not attached is thinned by grinding.
FIG. 10 is a cross-sectional view schematically showing a conventional BGA type semiconductor device having a supporting body. A semiconductor integrated circuit 101 configured of elements such as a CCD (Charge Coupled Device) image sensor or a CMOS image sensor is formed on the front surface of a semiconductor substrate 100 made of silicon (Si) or the like, and pad electrodes 102 electrically connected to the semiconductor integrated circuit 101 are further formed with an insulation film 103 being interposed therebetween. The pad electrodes 102 are covered by a passivation film 104 made of a silicon nitride film or the like.
A supporting body 105 made of a glass substrate is attached to the front surface of the semiconductor substrate 100 with an adhesive layer 106 made of epoxy resin or the like being interposed therebetween. The supporting body 105 is formed thick for firmly supporting the semiconductor substrate 100 which is to be thinned in the manufacturing process and preventing the supporting body 105 itself from warping or breaking. For example, if the semiconductor substrate 100 is about 100 μm in thickness after it is thinned, the supporting body 105 is about 400 μm in thickness.
An insulation film 107 made of a silicon oxide film, a silicon nitride film or the like is formed on the side and back surfaces of the semiconductor substrate 100. Furthermore, wiring layers 108 electrically connected to the pad electrodes 102 are formed on the insulation film 107 along the side and back surfaces of the semiconductor substrate 100. A protection film 109 made of a solder resist or the like is formed covering the insulation film 107 and the wiring layers 108. Openings are formed in predetermined regions of the protection film 109, and ball-shaped conductive terminals 110 are formed being electrically connected to the wiring layers 108 through these openings.
Such a semiconductor device is produced through a cutting process (a so-called dicing process) in which the supporting body 105, the protection film 109 and so on are cut along predetermined dicing lines DL as boundaries of devices into the individual devices with a dicing blade.
This type of art is described in Japanese Patent Application Publication No. 2006-93367, for example.
In the above described semiconductor device, the supporting body 105 made of a glass substrate remain exposed after it is diced. Since the glass side surface which is damaged by the dicing is exposed, it is likely that the glass cracks or breaks due to a physical impact from outside.
Although an IR cut coating may be formed on a primary surface of the supporting body 105 in order to cut a certain wavelength of light for application to an illumination sensor, the IR cut coating is not formed on a side surface of the supporting body 105, because it is difficult to form an IR cut coating on the side surface. Therefore, when there is incident light on the that side surface, the interference IR cut coating does not effectively cut oblique incident light and thus may cause the device property degrading. This influence is becoming a matter of concern particularly as the distance between a die end portion and a light receiving element is becoming shorter due to reduction in the die size.